Detection of one or more interstitial constituents in a polycrystalline diamond element by neutron radiographic imaging

ABSTRACT

In an embodiment, a method of non-destructively testing a polycrystalline diamond (“PCD”) element includes providing a PCD element including a plurality of bonded diamond grains defining a plurality of interstitial regions, at least a portion of the plurality of interstitial regions including one or more interstitial constituents disposed therein. The method further includes exposing the PCD element to neutron radiation from a neutron radiation source, receiving a portion of the neutron radiation that passes through the PCD element, and determining at least one characteristic of the PCD element at least partially based on the portion of the neutron radiation received. For example, the at least one characteristic may be the presence and distribution of metal-solvent catalyst, residual metal-solvent catalyst, an infiltrant, residual infiltrant, or other interstitial constituents within a PCD element.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/394,826 filed 20 Oct. 2010, which is incorporated herein, in itsentirety, by this reference.

BACKGROUND

Wear-resistant, polycrystalline diamond compacts (“PDCs”) are employedin a variety of mechanical applications. For example, PDCs are used indrilling tools (e.g., cutting elements, gage trimmers, etc.), machiningequipment, bearing apparatuses, wire-drawing machinery, and in othermechanical apparatuses.

PDCs have found particular utility as superabrasive cutting elements inrotary drill bits, such as roller-cone drill bits and fixed-cutter drillbits. A PDC cutting element typically includes a superabrasive diamondlayer commonly known as a diamond table. The diamond table is formed andbonded to a cemented carbide substrate using ahigh-pressure/high-temperature (“HPHT”) process. The PDC cutting elementmay be brazed directly into a preformed pocket, socket, or otherreceptacle formed in a bit body. The cemented carbide substrate mayoften be brazed or otherwise joined to an attachment member, such as acylindrical backing. A rotary drill bit typically includes a number ofPDC cutting elements affixed to the bit body. It is also known that astud carrying the PDC may be used as a PDC cutting element when mountedto a bit body of a rotary drill bit by press-fitting, brazing, orotherwise securing the stud into a receptacle formed in the bit body.

Conventional PDCs are normally fabricated by placing a cemented tungstencarbide substrate into a container with a volume of diamond particlespositioned on a surface of the cemented tungsten carbide substrate. Anumber of such containers may be loaded into an HPHT press. Thesubstrate(s) and volume(s) of diamond particles are then processed underdiamond-stable HPHT conditions. During the HPHT process, a metal-solventcatalyst cementing constituent of the cemented tungsten carbidesubstrate, such as cobalt from a cobalt-cemented tungsten carbidesubstrate, liquefies and infiltrates into interstitial regions betweenthe diamond particles. The cobalt acts as a catalyst to promoteintergrowth between the diamond particles, which results in formation ofa polycrystalline diamond (“PCD”) table of bonded diamond grains havingdiamond-to-diamond bonding therebetween that is bonded to the cementedtungsten carbide substrate. Interstitial regions between the bondeddiamond grains are occupied by the metal-solvent catalyst.

Once formed, the PCD table may be leached so as to remove at least aportion of the cobalt or other metal-solvent catalyst, as the continuedpresence of such metal-solvent catalyst within the working surfaces ofthe PCD table can greatly decrease performance characteristics of thePCD table. For example, the wear resistance and thermal stability of aPCD table may be adversely affected by the presence of cobalt.

In order to accurately predict the quality and performance of PDCs,manufacturers and users of PDCs continue to seek improvednon-destructive testing methods for testing PDCs.

SUMMARY

Embodiments of the invention relate to non-destructive testing methodsfor determining at least one characteristic of a PCD element, such as aPCD table of a PDC for use on a rotary drill bit. For example, the atleast one characteristic may be the presence and distribution ofmetal-solvent catalyst, residual metal-solvent catalyst, an infiltrant,residual infiltrant, or other interstitial constituents within a PCDelement. In an embodiment, a method of non-destructively testing a PCDelement includes providing a PCD element including a plurality of bondeddiamond grains defining a plurality of interstitial regions, with atleast a portion of the plurality of interstitial regions including oneor more interstitial constituents disposed therein. The method furtherincludes exposing the PCD element to neutron radiation from a neutronradiation source, receiving a portion of the neutron radiation thatpasses through the PCD element, and determining at least onecharacteristic of the PCD element at least partially based on theportion of the neutron radiation received.

The use of neutron radiographic imaging may enable non-destructivetesting of the manufactured product at significantly better resolutioncompared to alternative (e.g., X-ray) non-destructive imagingtechniques. Furthermore, neutron radiographic imaging providesinformation relative to the presence and distribution of metal-solventcatalyst used to catalyze formation of the PCD element, residualmetal-solvent catalyst remaining after subjecting the PCD element to aleaching process, infiltrant that infiltrates an at least partiallyleached PCD element during re-attachment to a substrate, or residualinfiltrant remaining after subjecting a re-attached and infiltrated PCDelement to a leaching process. In addition to providing greaterresolution with respect to the presence and distribution of any residualmetal-solvent catalyst or infiltrant, neutron radiographic imaging alsoenables detection of relatively light chemical elements and/or molecules(e.g., contaminants) such as hydrogen, oxygen, nitrogen, water, andother chemicals such as salts and oxides, which is an example of anotherinterstitial constituent that may be detected by the inventive methodsdisclosed herein. Such elements and/or molecules may be introduced tothe PCD element as by-products of the leaching process used to depletemetal-solvent catalyst and/or infiltrant from the PCD element.

Other embodiments include applications utilizing the non-destructivelytested PCD elements and PDCs in various articles and apparatuses, suchas rotary drill bits, machining equipment, and other articles andapparatuses.

Features from any of the disclosed embodiments may be used incombination with one another, without limitation. In addition, otherfeatures and advantages of the present disclosure will become apparentto those of ordinary skill in the art through consideration of thefollowing detailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate several embodiments of the invention, whereinidentical reference numerals refer to identical elements or features indifferent views or embodiments shown in the drawings.

FIG. 1A is a cross-sectional view of an embodiment of a PDC, the PDCincluding a PCD table attached to a cemented carbide substrate;

FIG. 1B is a cross-sectional view of an embodiment of a PDC including aleached PCD table;

FIG. 1C is an enlarged schematic cross-sectional view of the PCD tableof the PDC of FIG. 1A after a portion of the PCD table has been leached;

FIG. 1D is a schematic cross-sectional view of a partially leached PCDtable having a leached region and an un-leached region formed byclusters;

FIGS. 2A and 2B are radiographic images of a PCD table showing thepresence of clusters of metal-solvent catalyst;

FIG. 3 is a flow chart of a non-destructive testing method according toan embodiment of the invention;

FIG. 4 is an isometric view of an embodiment of a rotary drill bit thatmay employ one or more of the PCD elements and/or PDCs non-destructivelytested according to one or more embodiments of the invention; and

FIG. 5 is a top elevation view of the rotary drill bit shown in FIG. 4.

DETAILED DESCRIPTION I. Introduction

Embodiments of the invention relate to non-destructive testing methodsfor evaluating the quality of manufactured PCD elements (e.g., a PCDtable of a PDC) in which at least a portion of the PCD element isexposed to neutron radiation from a neutron radiation source, a portionof the neutron radiation that passes through the PCD element isreceived, and at least one characteristic of the PCD element isdetermined based at least partially on the portion of the neutronradiation received. For example, such testing may reveal the presenceand distribution of metal-solvent catalyst, an infiltrant, residualmetal-solvent catalyst, residual infiltrant, one or more light chemicalelements, one or more light chemical molecules, other interstitialconstituents (e.g., salts and/or oxides), or combinations thereof(collectively referred to herein as interstitial constituents) withinthe interstitial regions of the PCD table. Such methods are particularlybeneficial in evaluating at least that portion of the PCD table that isadjacent to exterior working surfaces of the PCD table that have been atleast partially leached.

II. PCD Elements and PDCs

FIG. 1A is a cross-sectional view of an embodiment of a PDC 100including a PCD table 102 attached to a substrate 108. The PCD table 102may be formed integral with or separately from the substrate 108. Whenformed separately, the PCD table 102 may be subsequently attached to thesubstrate 108. When the PCD table 102 is formed separate from thesubstrate 108 and subsequently attached to the substrate 108, aninfiltrant (e.g., cobalt) from the substrate 108 may infiltrate into thePCD table 102 during an HPHT process in which the PCD table 102 becomesmetallurgically bonded to substrate 108. Referring to FIG. 1B, in anycase, the PCD table 102 may be at least partially leached (e.g., with asuitable acid) so as to remove some or all of the metal-solvent catalystor infiltrant residing within the interstitial regions to form a leachedregion 103. The leaching may be performed to a PCD table that isattached to a cemented carbide substrate 108 or a PCD table that isseparate from any such substrate.

The PCD table 102 includes a plurality of directly bonded-togetherdiamond grains exhibiting diamond-to-diamond bonding (e.g., sp³ bonding)therebetween, which define a plurality of interstitial regions. The PCDtable 102 includes at least one lateral surface 104 and an upperexterior working surface 106. It is noted that at least a portion of theat least one lateral surface 104 may also function as a working surfacethat contacts a subterranean formation during drilling operations. Insome embodiments, a chamfer may extend between the lateral surface 104and working surface 106.

In an embodiment, the substrate 108 comprises a plurality of tungstencarbide or other carbide grains (e.g., tantalum carbide, vanadiumcarbide, niobium carbide, chromium carbide, and/or titanium carbide)cemented together with a metallic cementing constituent, such as cobalt,iron, nickel, or alloys thereof. For example, in an embodiment, thesubstrate 108 may be a cobalt-cemented tungsten carbide substrate. Insome embodiments, the substrate 108 may include two or more differentcarbides (e.g., tungsten carbide and titanium carbide).

In an embodiment, the PCD table 102 is formed while simultaneously beingmetallurgically bonded with substrate 108. For example, a plurality ofdiamond particles may be positioned on an upper surface of the substrate108, and the diamond particles and the substrate 108 may be placed in apressure transmitting medium, such as a refractory metal can embedded inpyrophyllite or other pressure transmitting medium. The pressuretransmitting medium, including the substrate 108 and diamond particlestherein may be subjected to an HPHT process using an ultra-high pressurepress to create temperature and pressure conditions at which diamond isstable. The temperature of the HPHT process may be at least about 1000°C. (e.g., about 1200° C. to about 1600° C.) and the pressure of the HPHTprocess may be at least 4.0 GPa (e.g., about 5.0 GPa to about 10.0 GPa)for a time sufficient to sinter the diamond particles to form the PCDtable 102. For example, the pressure of the HPHT process may be about 5GPa to about 7 GPa and the temperature of the HPHT process may be about1150° C. to about 1450° C. (e.g., about 1200° C. to about 1400° C.).

During the HPHT process, the cementing constituent from the substrate108 may be liquefied and may infiltrate into the diamond particles. Theinfiltrated cementing constituent functions as a metal-solvent catalystthat catalyzes formation of directly bonded-together diamond grains toform the PCD table 102. In embodiments in which the diamond particleswere sintered previously, the metal-solvent cementing constituent simplyinfiltrates into the interstitial regions between adjacent diamondgrains of the PCD table, resulting in a metallurgical bond between thePCD table 102 and the substrate 108.

As an alternative to providing the substrate 108 during sintering of thediamond particles, the PCD table 102 may be formed by placing thediamond particles along with a metal-solvent catalyst (e.g., cobaltpowder and/or a cobalt disc) in a pressure transmitting medium, such asa refractory metal can embedded in pyrophyllite or other gasket medium.The pressure transmitting medium, including the diamond particles andmetal-solvent catalyst therein, may be subjected to an HPHT processusing an ultra-high pressure press to create temperature and pressureconditions at which diamond is stable. Such a process will result in themetal-solvent catalyst catalyzing direct bonding between diamond grains.At completion of the process, the metal-solvent catalyst resides withininterstitial regions between the diamond grains, resulting in formationof a PCD table 102 separate from any cemented carbide substrate 108.

Even when the PCD table 102 is formed on the substrate 108, the PCDtable 102 may be singulated to be freestanding by removing the substrate108 using a suitable material removal process, such as grinding,electro-discharge machining, or combinations thereof. The freestandingPCD table may be leached to substantially remove all of themetal-solvent catalyst therefrom, and attached to a substrate (e.g., acobalt-cemented tungsten carbide substrate) in a subsequent HPHT processso that an infiltrant from the substrate (e.g., cobalt from acobalt-cemented tungsten carbide substrate) at least partiallyre-infiltrates the PCD table.

Removal of the metal-solvent catalyst or infiltrant from the PCD tablethat is freestanding or bonded to a substrate is beneficial as itincreases the wear resistance and/or thermal stability the PCD table102. For this reason, substantially all of the metal-solvent catalyst ofa PCD table (e.g., adjacent to the working surface 106 and lateralsurface 104) may subsequently be depleted of the metal-solvent catalystor infiltrant via a leaching process by exposure to a suitable acid(e.g., aqua regia, nitric acid, hydrofluoric acid, or other suitableacid), and attached to a substrate 108 and infiltrated with aninfiltrant from the substrate 108. For example, at least a portion ofthe PCD table may be immersed in the acid for about 2 to about 7 days(e.g., about 3, 5, or 7 days) or for a few weeks (e.g., about 2 to about4 weeks) depending on the process employed. The leaching time andcompleteness of the metal-solvent catalyst or infiltrant removal dependson the porosity of the PCD table, among other factors. For example,decreased porosity exponentially decreases the completeness of depletionand/or requires additional leaching time.

Substantially all of the metal-solvent catalyst or infiltrant of the PCDtable 102 that is bonded to the substrate 108 (e.g., adjacent to theworking surface 106 and lateral surface 104) may also subsequently bedepleted of the metal-solvent catalyst or infiltrant via a leachingprocess by exposure to any of the previously mentioned acids. Forexample, the leaching process may remove substantially all of themetal-solvent catalyst or infiltrant to a selected depth from theworking surface 106 of about 50 μm to about 1000 μm (e.g., about 200 μmto about 500 μm) after a period of about 2 to about 4 weeks. Typically,leaching may not remove all of the metal-solvent catalyst or infiltrantwithin the leached region. For example, it is typical for the averageconcentration of residual metal-solvent catalyst or infiltrant to beabout 0.5% to about 2% by weight, more typically 0.9% to about 1% byweight after leaching within the leached region. The residualmetal-solvent catalyst or infiltrant may be measured, for example, byenergy dispersive spectroscopy or magnetic saturation measurements.

III. Structure of Metal-Solvent Catalyst or Infiltrant Clusters

It is believed that even though the average concentration of themetal-solvent catalyst or infiltrant within the leached portion of thePCD table 102 is thus relatively low (e.g., no more than about 2% byweight), the distribution of residual metal-solvent catalyst orinfiltrant within the leached portion may not be substantially uniform.In other words, the residual metal-solvent catalyst or infiltrant may bepresent as clusters including a plurality of portions in which theclusters of metal-solvent catalyst or infiltrant may be surrounded bydiamond grains and interstitial regions containing little or nometal-solvent catalyst or infiltrant portions. Although the averageconcentration of metal-solvent catalyst or infiltrant may thus berelatively low (e.g., no more than about 2% by weight) within theleached region overall, there may be subregions within the leachedregion in which the presence of one or more clusters results in aconcentration of metal-solvent catalyst or infiltrant that issignificantly higher within the subregion.

Although not entirely understood, such clusters may remain even afterleaching as a result of lower porosity in the subregion where theclusters remain and/or limited circulation in the acid leaching bathused to deplete the metal-solvent catalyst or infiltrant from the PCDtable. Because the degree of completeness of metal-solvent catalyst orinfiltrant removal depends exponentially on porosity, even a relativelymoderate decrease in porosity within such a subregion may result in thecontinued presence of one or more clusters of metal-solvent catalyst orinfiltrant remaining even after leaching for a significant period oftime (e.g., about 2 to about 4 weeks), and even after the averageconcentration of metal-solvent catalyst or infiltrant has dropped to nomore than about 2% by weight.

The presence of such clusters not only results in decreased wearresistance and/or thermal stability within the subregion in which thecluster is located, but also may result in problems, such asdelamination of the PCD table 102 from the substrate 108 and/or poorinfiltration of the PCD table 102 when the PCD table 102 is preformedand joined to a substrate in a separate attachment process. Furthermore,the presence of other interstitial constituents such as by-products ofthe leaching process (e.g., light chemical elements and/or lightmolecules, salts, oxides, or combinations thereof) may become trappedwithin the leached region of PCD table 102. For example, the lightchemical elements and/or light molecules may include hydrogen, oxygen,nitrogen, water, other contaminants (e.g., salts and/or oxides), orcombinations of the foregoing. The presence of such contaminants mayalso be detrimental to the performance characteristics of the PCD table.

FIG. 1C shows an enlarged schematic cross-sectional view of the PCDtable 102 including the leached region 103 shown in FIG. 1B adjacent tothe working surface 106 and an un-leached region 105 below leachedregion 103 (e.g., adjacent to the substrate 108 (not shown)). Althoughthe average concentration of metal-solvent catalyst or infiltrant 107may be relatively low (e.g., no more than about 2% by weight) withinleached region 103, the distribution of metal-solvent catalyst orinfiltrant 107 may be non-uniform, including concentrated clusters 109in which the atoms, particles, or other portions thereof areconcentrated in close proximity to one another. Furthermore, otherinterstitial constituents, such as relatively light weight elementsand/or molecules (e.g., having a molecular weight less than about 40),such as hydrogen, oxygen, nitrogen, water, or combinations thereof maybe present within leached region 103 as by-products of the leachingprocess or as contaminants derived from other sources. Additionally,other interstitial constituents, such as salts and oxides (e.g., cobaltsalts and oxides), may be present within leached region 103 asby-products of the leaching process or as contaminants derived fromother sources. The presence of such contaminants may also be detrimentalto the performance characteristics of PCD table 102 and/or there-infiltration of an at least partially leached PCD table during are-attachment to a substrate. Of course, such contaminants may also bepresent within un-leached region 105. In addition to detecting thepresence of such interstitial constituents, the non-destructive testingmay also show a location and configuration of an interface 110 betweenthe leached region 103 and the un-leached region 105 of the PCD table102.

FIG. 1D is a schematic cross-sectional view of a partially leached PCDtable 120 having a leached region 122 and an un-leached region 124formed by clusters having a different arrangement than shown in FIG. 1C.For example, the un-leached region 124 may be generally centrallylocated in the partially leached PCD table 120 and defines a disk-likestructure.

By way of example to merely illustrate the structure of clusters ofmetal-solvent catalyst, FIGS. 2A and 2B show images of PCD tables takenwith x-ray radiography, which include clusters of metal-solvent catalystdisposed within at least a portion of the interstitial regions of thePCD table. The clusters are the darker regions in the images in FIGS. 2Aand 2B. For example, a cluster that is shown in FIG. 2A may occur as aresult of incomplete leaching (e.g., resulting from very low porosity).FIG. 2B shows a PCD table in which relatively smaller clusters aredispersed away from the center of the PCD table, in a pattern that isgenerally concentric relative to the “clean” center of the PCD table.

III. Neutron Radiographic Non-Destructive Testing Methods

Any of the aforementioned PCD tables (whether freestanding or attachedto a substrate) may be non-destructively tested using neutronradiographic imaging. FIG. 3 is a flow chart of a non-destructivetesting method 200 according to an embodiment of the invention, whichmay be used to non-destructively test a PCD table. In act 202, a PCDtable may be provided. The PCD table may be freestanding and leached orun-leached, or attached to a substrate and leached or un-leached. Inorder to detect the presence of anomalies within the PCD table 102, inact 204, the PCD table 102 may be exposed to neutron radiation (e.g.,neutron beam) from a neutron radiation source. In act 206, a portion ofthe neutron radiation passes through the PCD table and is received by adetector (e.g., a radiation detector or photosentive film) so that animage of the PCD table showing the presence of interstitial constituentsdisposed within the interstitial regions between the diamond grains andthe diamond grains is generated. In act 208, one or more characteristicsof the PCD table may be determined at least partially based upon theportion of neutron radiation received.

The one or more characteristics of the PCD table determined may be thepresence and distribution of metal-solvent catalyst in the PCD table,residual metal-solvent catalyst in the PCD table, an infiltrant in thePCD table, residual infiltrant in the PCD table, other interstitialconstituents (e.g., light elements and/or molecules) within the PCDtable, or combinations of the foregoing. As another example, when thePCD table is attached to a substrate (e.g., the PCD table 102 shown inFIG. 1B), the method 200 may be used to determine the location of theinterface 110 (e.g., leach depth) and/or any of the other of the one ormore characteristics.

Use of a neutron beam imaging technique can be advantageous overalternative testing and/or detection methods, as it is non-destructive,and provides for better resolution as compared to alternative radiationimaging techniques (e.g., X-ray and/or gamma ray). For example, withX-ray and gamma ray imaging, the detection of many light weightcontaminants is not possible.

Any suitable neutron radiation source may be used. For example, coldneutron radiation sources, thermal neutron radiation sources, fastneutron radiation sources, or combinations thereof may be employed inthe neutron beam imaging technique. By way of non-limiting example, coldneutron sources may exhibit energies of less than about 0.025 eV,thermal neutrons may exhibit energies of between about 0.025 eV andabout 1 eV (e.g., perhaps most typically about 0.025 eV), and fastneutrons may exhibit energies of at least about 1 keV (e.g., even ashigh as 14 MeV or greater). Cold and/or thermal neutron sources may beparticularly preferred in some embodiments, as they may exhibit greatercontrast (as compared to fast neutrons) between different elementsand/or molecules within the PCD table being examined. Although fastneutron sources may exhibit lower contrast, they may also have a greaterability to penetrate to a greater thickness.

Imaging with neutrons may involve production of images on film, digitalproduction of images, or the production of three-dimensional data(tomography). The neutron flux for generating the neutron beam used inimaging may be produced from conventional sources, such as nuclearreactors (e.g., producing cold, thermal and/or fast neutrons), ordeuteron-tritium tubes (i.e., D-T tubes) in which a deuteron beamimpinges upon a tritiated target, which yields fast neutrons (e.g., 14MeV neutrons). Such fast neutrons may be used directly for fast neutronimaging or may be moderated to a lower temperature to allow thermal orperhaps even cold neutron imaging. Accelerators for accelerating beamsof protons or deuterons are another exemplary source of neutrons.

The manufacturing process and/or precursor materials used to fabricatethe PCD elements (e.g., the PCD tables and/or PDCs) may be adjusted inresponse to the non-destructive neutron radiographic imaging via themethod 200. For example, the HPHT process conditions (e.g., pressure,temperature, time, or combinations thereof), leaching acid composition,leaching time, diamond particle size, or combinations of the foregoingmay be modified in view of the results of the non-destructive neutronradiographic imaging via the method 200.

In some cases, one or more samples of manufactured PCD tables may besent to a third party for neutron imaging, or the testing may be done bythe manufacturer, depending on the availability of the neutron source.

The non-destructively tested PCD elements and PDCs may be installed on arotary drill bit. FIG. 4 is an isometric view and FIG. 5 is a topelevation view of an embodiment of a rotary drill bit 300 that includesat least one PDC configured according to any of the disclosed PDCembodiments. The rotary drill bit 300 comprises a bit body 302 thatincludes radially and longitudinally extending blades 304 having leadingfaces 306, and a threaded pin connection 308 for connecting the bit body302 to a drilling string. The bit body 302 defines a leading endstructure for drilling into a subterranean formation by rotation about alongitudinal axis 310 and application of weight-on-bit. At least one PCDelement (e.g., a PDC), manufactured and/or non-destructively testedaccording to any of the previously described embodiments, may be affixedto the bit body 302. With reference to FIG. 5, each of a plurality ofPDCs 312 is secured to the blades 304 of the bit body 302 (FIG. 4). Forexample, each PDC 312 may include a PCD table 314 bonded to a substrate316. More generally, the PDCs 312 may comprise any PDC disclosed herein,without limitation, which is configured and non-destructively testedaccording to any of the previously described embodiments.Circumferentially adjacent blades 304 define so-called junk slots 320therebetween. Additionally, the rotary drill bit 300 includes aplurality of nozzle cavities 318 for communicating drilling fluid fromthe interior of the rotary drill bit 300 to the PDCs 312.

FIGS. 4 and 5 merely depict one embodiment of a rotary drill bit thatemploys at least one PDC tested and structured in accordance with thedisclosed embodiments, without limitation. The rotary drill bit 300 isused to represent any number of earth-boring tools or drilling tools,including, for example, core bits, roller-cone bits, fixed-cutter bits,eccentric bits, bi-center bits, reamers, reamer wings, or any otherdownhole tool including superabrasive compacts, without limitation.

The tested PCD elements disclosed herein (e.g., PDC 100 of FIG. 1A) mayalso be utilized in applications other than cutting technology. Forexample, the disclosed PDC embodiments may be used in wire dies,bearings, artificial joints, inserts, cutting elements, and heat sinks.Thus, any of the PDCs and other PCD elements disclosed herein may beemployed in an article of manufacture including at least onesuperabrasive element or compact.

Thus, the tested PCD element disclosed herein may be used in anyapparatus or structure in which at least one conventional PCD element istypically used. In an embodiment, a rotor and a stator, assembled toform a thrust-bearing apparatus, may each include one or more PDCs(e.g., PDC 100 of FIG. 1A) configured according to any of theembodiments disclosed herein and may be operably assembled to a downholedrilling assembly. U.S. Pat. Nos. 4,410,054; 4,560,014; 5,364,192;5,368,398; and 5,480,233, the disclosure of each of which isincorporated herein, in its entirety, by this reference, disclosesubterranean drilling systems within which bearing apparatuses utilizingsuperabrasive compacts disclosed herein may be incorporated. Theembodiments of PCD elements disclosed herein may also form all or partof heat sinks, wire dies, bearing elements, cutting elements, cuttinginserts (e.g., on a roller-cone-type drill bit), machining inserts, orany other article of manufacture as known in the art. Other examples ofarticles of manufacture that may use any of the tested PDCs disclosedherein are disclosed in U.S. Pat. Nos. 4,811,801; 4,268,276; 4,468,138;4,738,322; 4,913,247; 5,016,718; 5,092,687; 5,120,327; 5,135,061;5,154,245; 5,460,233; 5,544,713; and 6,793,681, the disclosure of eachof which is incorporated herein, in its entirety, by this reference.

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments are contemplated. The various aspects andembodiments disclosed herein are for purposes of illustration and arenot intended to be limiting. Additionally, the words “including,”“having,” and variants thereof (e.g., “includes” and “has”) as usedherein, including the claims, are open ended and shall have the samemeaning as the word “comprising” and variants thereof (e.g., “comprise”and “comprises”).

What is claimed is:
 1. A method of non-destructively testing apolycrystalline diamond element, comprising: providing an at leastpartially leached polycrystalline diamond element including a pluralityof bonded diamond grains defining a plurality of interstitial regions,at least a portion of the plurality of interstitial regions includingone or more interstitial constituents comprising at least one leachingby-product disposed therein; exposing the at least partially leachedpolycrystalline diamond element to neutron radiation from a neutronradiation source; receiving a portion of the neutron radiation thatpasses through the at least partially leached polycrystalline diamondelement; and determining at least one characteristic of the at leastpartially leached polycrystalline diamond element at least partiallybased on the portion of the neutron radiation received, the at least onecharacteristic including a presence of the at least one leachingby-product.
 2. The method of claim 1 wherein determining at least onecharacteristic of the at least partially leached polycrystalline diamondelement at least partially based on the portion of the neutron radiationreceived comprises determining the presence of clusters of metal-solventcatalyst or infiltrant disposed within a portion of the interstitialregions.
 3. The method of claim 1 wherein determining at least onecharacteristic of the at least partially leached polycrystalline diamondelement at least partially based on the portion of the neutron radiationreceived comprises determining the presence of one or more lightchemical elements and/or light chemical molecules.
 4. The method ofclaim 3 wherein the light chemical elements and/or light chemicalmolecules are selected from hydrogen, oxygen, nitrogen, water, andcombinations thereof.
 5. The method of claim 1 wherein the at leastpartially leached polycrystalline diamond element comprises an at leastpartially leached polycrystalline diamond table, and wherein determiningat least one characteristic of the at least partially leachedpolycrystalline diamond element at least partially based on the portionof the neutron radiation received comprises determining a location of aninterface between a first region that extends inwardly from an exteriorworking surface of the at least partially leached polycrystallinediamond table and is substantially free of metal-solvent catalyst, and asecond region of the at least partially leached polycrystalline diamondtable that comprises the metal-solvent catalyst.
 6. The method of claim1 wherein the at least partially leached polycrystalline diamond elementcomprises an at least partially leached polycrystalline diamond table,and wherein determining at least one characteristic of the at leastpartially leached polycrystalline diamond element at least partiallybased on the portion of the neutron radiation received comprisesdetermining a location of an interface between a first region thatextends inwardly from an exterior working surface of the at leastpartially leached polycrystalline diamond table and is substantiallyfree of an infiltrant, and a second region of the at least partiallyleached polycrystalline diamond table that comprises the infiltrant. 7.The method of claim 1 wherein the neutron radiation is provided by acold neutron beam source.
 8. The method of claim 1 wherein the neutronradiation is provided by a thermal neutron beam source.
 9. The method ofclaim 1 wherein the neutron radiation is provided by a fast neutron beamsource.
 10. The method of claim 1 wherein the one or more interstitialconstituents comprise metal-solvent catalyst, an infiltrant, residualmetal-solvent catalyst, residual infiltrant, one or more light chemicalelements, one or more light chemical molecules, or combinations thereof.11. The method of claim 1 wherein the at least partially leachedpolycrystalline diamond element is freestanding.
 12. The method of claim1 wherein the at least partially leached polycrystalline diamond elementis attached to a substrate.
 13. The method of claim 1 wherein the atleast partially leached polycrystalline diamond element is integrally orpreformed and attached to a substrate.
 14. The method of claim 1,further comprising modifying a manufacturing process used to fabricatethe at least partially leached polycrystalline diamond element inresponse to the determined at least one characteristic.
 15. The methodof claim 1 wherein modifying a manufacturing process used to fabricatethe at least partially leached polycrystalline diamond element inresponse to the determined at least one characteristic comprisesmodifying a high-pressure/high-temperature process condition used tofabricate the at least partially leached polycrystalline diamondelement.
 16. The method of claim 15 wherein thehigh-pressure/high-temperature process condition comprises pressure,temperature, time, or combinations thereof.
 17. The method of claim 1wherein modifying a manufacturing process used to fabricate the at leastpartially leached polycrystalline diamond element in response to thedetermined at least one characteristic comprises modifying a leachingacid composition, leaching time, diamond particle size, or combinationsthereof.
 18. A method of non-destructively testing a polycrystallinediamond element, comprising: providing an at least partially leachedpolycrystalline diamond element including a plurality of bonded diamondgrains defining a plurality of interstitial regions, at least a portionof the plurality of interstitial regions including one or moreinterstitial constituents disposed therein; and exposing the at leastpartially leached polycrystalline diamond element to neutron radiationfrom a neutron radiation source; receiving a portion of the neutronradiation that passes through the at least partially leachedpolycrystalline diamond element; and at least partially based on theportion of the neutron radiation received, determining a presence of oneor more interstitial constituents including at least one leachingby-product within a portion of the interstitial regions of the at leastpartially leached polycrystalline diamond element; and correlating thedetermined presence of the at least one leaching by-product within theportion of the interstitial regions with at least one performancecharacteristic of the at least partially leached polycrystalline diamondtable.
 19. The method of claim 1, further comprising: correlating thepresence of the at least one leaching by-product in the at leastpartially leached polycrystalline diamond element to at least oneperformance characteristic of the at least partially leachedpolycrystalline diamond element; and modifying a manufacturing processused to fabricate the at least partially leached polycrystalline diamondelement in response to the at least one performance characteristic. 20.The method of claim 18, further comprising modifying a manufacturingprocess used to fabricate the at least partially leached polycrystallinediamond element in response to the at least one performancecharacteristic.